Catheter with injection needle

ABSTRACT

An injection catheter is provided. The catheter comprises a catheter body comprising a flexible tubing having proximal and distal ends and at least one lumen therethrough. The catheter further comprises a tip section comprising a flexible tubing having proximal and distal ends. The proximal end of the tip section is mounted at the distal end of the catheter body. A needle control handle is provided at the proximal end of the catheter body. An injection needle extends through the tip section, catheter body, and needle control handle and has a proximal end attached to the needle control handle and a distal end within the tip section. The injection needle is longitudinally slidable within the tip section so that its distal end can extend beyond the distal end of the tip section upon suitable manipulation of the needle control handle. The injection needle consists of plastic.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.09/562,612, filed May 1, 2000 now U.S. Pat. No. 6,575,931 which claimspriority of U.S. Provisional Patent Application No. 60/165,354, filedNov. 12, 1999; U.S. patent application Ser. No. 09/562,612 is also acontinuation-in-part of U.S. patent application Ser. No. 09/280,202,filed Mar. 29, 1999, now U.S. Pat. No. 6,165,164 which claims priorityof U.S. Provisional Patent Application Nos. 60/088,019, filed Jun. 4,1998, and 60/088,984, filed on Jun. 11, 1998, the entire disclosures ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to a catheter for infusing therapeutic ordiagnostic agents into the tissue of organs having an improved injectionneedle.

BACKGROUND OF THE INVENTION

Targeted delivery of therapeutic or diagnostic agents, such as occurs ingene therapy, is very desirable but often presents a difficultchallenge. A potential benefit of targeted delivery is that there is anincreased efficiency obtained by the precise placement of thetherapeutic agent. There are several problems to his procedure whichmust be overcome in order to obtain satisfactory results from suchtherapy, such as the problems of obtaining access to the delivery site,transporting the therapeutic agent to the desired site, injecting thetherapeutic agent at the proper depth within the organ tissue, steeringthe distal end of the catheter to a desired location within the organprior to infusing the agent, and positioning the distal tip of thecatheter at precisely the same location where prior measurements haveindicated that the drug should be infused. It is also important to for aphysician to be able to monitor the position of the infusion needle withrespect to the wall of the organ. In the case of an organ, such as theheart, in which the walls are in constant motion, the activity ofpositioning and monitoring the position of the distal tip of thecatheter, or infusion needle, becomes especially difficult.

U.S. Pat. No. 3,598,119 discloses a medical device for injecting drugsin which the injection needle is guided through an inner lumen of acatheter for insertion of the needle under skin tissue. A bladder at thedistal end of the catheter may be inflated through another lumen forholding the point of the needle point in a fixed position beneath theskin.

U.S. Pat. No. 4,578,061 discloses a catheter for injecting a liquid intoa vein, or artery, through an injection needle which is longitudinallymovable beyond the distal end of the catheter. A dual chamber system isutilized within the catheter tip to provide for movement of a plunger toextend the injection needle and also to allow for a plunger to be usedto apply a predetermined dose of medication through the injectionneedle.

U.S. Pat. No. 4,578,061 discloses an injection catheter having alongitudinal movable needle which may be moved through a lumen in orderto extend out of the side wall of the catheter for injecting a liquidinto a blood vessel. The needle is normally retracted into the device sothat the needle will not penetrate tissue as the device is moved througha body duct. Thereafter, the needle is moved out of the side of thecatheter into a vessel wall in order to infuse a liquid into the wall ofa vessel.

U.S. Pat. No. 5,244,460 is directed toward a method for improving bloodflow to the heart. More particularly this patent is directed toward amedical procedure for improving the growth of cardiac blood vessels byinserting a catheter into a coronary artery and injecting into the hearta blood vessel growth promoting peptide through an injection port of thecatheter.

U.S. Pat. No. 5,419,777 is directed toward a catheter for injection of afluid into body cavities such as coronary vessels and arteries. Thispatent, as is the case with the '061 patent, illustrates the use of aninjection needle which protrudes laterally through the side walls of thedistal tip of the catheter. In the case of drug injections to be madeinto coronary vessels and arteries, it is very desirable to have theneedles extend out of the side walls of the catheter and at an acuteangle to the walls of the vessel in order to penetrate the walls of thevessel for injection of the agent.

U.S. Pat. No. 5,431,168, assigned to the same assignee as the presentpatent application, is directed toward a steerable catheter whichincludes a puller wire for controlling the distal end of the catheterfrom a control handle which is mounted on the proximal end of thecatheter.

Copending U.S. patent application Ser. No. 09/019,453, entitled“Intracardiac Drug Delivery,” assigned to an affiliated company of theassignee of this application, discloses an injection catheter system forinfusing a diagnostic or therapeutic agent into the wall of an organwhich includes an electromagnetic sensor disposed within the distal tipof the catheter for providing very precise location information for thedistal tip of the catheter. The subject matter of this copending patentapplication is incorporated by reference into the subject patentapplication.

Copending U.S. patent application Ser. No. 09/280,202 describes aninjection catheter with an injection needle is made of Nitinol. Althougha Nitinol injection needle has several advantages, it is subject tocorrosion and can be expensive, particularly when used for an injectionneedle that extends the entire length of the catheter. Moreover, due tothe properties of Nitinol, it cannot be welded to dissimilar,less-expensive metals to produce a more cost-effective injection needle.

SUMMARY OF THE INVENTION

This present invention is directed to a catheter for infusingtherapeutic or diagnostic agents into the tissue of organs having animproved injection needle. More particularly, the invention is directedto an injection catheter comprising a catheter body made of a flexibletubing having proximal and distal ends and at least one lumentherethrough. The catheter further comprises a tip section comprising aflexible tubing having proximal and distal ends, wherein the proximalend of the tip section is mounted at the distal end of the catheterbody. One or more electrodes are mounted on the tip section. One or moreelectrode lead wires that correspond in number to the number ofelectrodes are provided, with each electrode lead wire having a distalend that is electrically connected to a corresponding electrode on thetip section.

A needle control handle is provided at the proximal end of the catheterbody. An injection needle extends through the tip section, catheterbody, and needle control handle and has a proximal end attached to theneedle control handle and a distal end within the tip section. Theinjection needle is longitudinally slidable within the tip section sothat its distal end can extend beyond the distal end of the tip sectionupon suitable manipulation of the needle control handle. The injectionneedle consists of plastic tubing.

DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will bebetter understood by reference to the following detailed descriptionwhen considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a side plan view of one embodiment of the catheter of thepresent invention.

FIG. 2 a is a side cross-sectional view of the needle control handlewhere the needle is in a retracted position.

FIG. 2 b is a side cross-sectional view of the needle control handlewhere the needle is in an extended position.

FIG. 3 is a side cross-sectional view of a tip section according to theinvention having three lumens, showing the position of theelectromagnetic mapping sensor and the injection needle.

FIG. 4 is a side cross-sectional view of the tip section of FIG. 3showing the position of the electromagnetic mapping sensor and thepuller wire.

FIG. 5 is a side cross-sectional view of the catheter body, includingthe junction between the catheter body and the section.

FIG. 6 is a transverse cross-sectional view of the tip section of FIG. 3along line 6—6 showing an embodiment having three lumens.

FIG. 7 is a transverse cross-sectional view of the catheter body of FIG.5 along line 7—7.

FIG. 8 is a side cross-sectional view of the catheter handle.

DETAILED DESCRIPTION

In a preferred embodiment of the invention, there is provided a catheterfor use for injection of a therapeutic or diagnostic agent into theheart. As shown in FIG. 1, catheter 10 comprises an elongated catheterbody 12 having proximal and distal ends, a tip section 14 at the distalend of the catheter body 12, a deflection control handle 16 at theproximal end of the catheter body 12, and a needle control handle 17proximal the catheter body.

With reference to FIGS. 5 and 7, the catheter body 12 comprises asingle, central or axial lumen 18. The catheter body 12 is flexible,i.e., bendable, but substantially non-compressible along its length. Thecatheter body 12 may be of any suitable construction and made of anysuitable material. A presently preferred construction comprises an outerwall 22 made of a polyurethane or nylon. The outer wall 22 comprises animbedded braided mesh of stainless steel or the like to increasetorsional stiffness of the catheter body 12 so that, when the controlhandle 16 is rotated, the tip section of the catheter 10 will rotate ina corresponding manner.

The outer diameter of the catheter body 12 is not critical, but ispreferably no more than about 8 French. Likewise the thickness of theouter wall 22 is not critical. The inner surface of the outer wall 22 islined with a stiffening tube 20, which can be made of any suitablematerial, preferably polyimide. The stiffening tube, along with thebraided outer wall 22, provides improved torsional stability while atthe same time minimizing the wall thickness of the catheter, thusmaximizing the diameter of the single lumen. The outer diameter of thestiffening tube 20 is about the same as or slightly smaller than theinner diameter of the outer wall 22. Polyimide tubing is presentlypreferred because it may be very thin walled while still providing verygood stiffness. This maximizes the diameter of the central lumen 18without sacrificing strength and stiffness. Polyimide material istypically not used for stiffening tubes because of its tendency to kinkwhen bent. However, it has been found that, in combination with an outerwall 22 of polyurethane, nylon or other similar material, particularlyhaving a stainless steel braided mesh, the tendency for the polyimidestiffening tube 20 to kink when bent is essentially eliminated withrespect to the applications for which the catheter is used. If desired,the stiffening tube 20 can be eliminated.

As shown in FIGS. 3, 4 and 6, the tip section 14 comprises a shortsection of tubing 19 having three lumens 30, 32 and 34. The tubing 19 ismade of a suitable non-toxic material which is preferably more flexiblethan the catheter body 12. A presently preferred material for the tubing19 is braided polyurethane, i.e., polyurethane with an embedded mesh ofbraided stainless steel or the like. The outer diameter of the tipsection 14, like that of the catheter body 12, is preferably no greaterthan about 8 French. The size of the lumens is not critical. In aparticularly preferred embodiment, the tip section has an outer diameterof about 7 French (0.092 inch) and the first lumen 30 and second lumen32 are generally about the same size, having a diameter of about 0.022inch, with the third lumen 34 having a slightly larger diameter of about0.036 inch.

A preferred means for attaching the catheter body 12 to the tip section14 is illustrated in FIG. 5. The proximal end of the tip section 14comprises an inner counter bore 24 that receives the outer surface ofthe polyimide stiffener 20. The tip section 14 and catheter body 12 areattached by glue or the like.

The stiffening tube 20 is held in place relative to the outer wall 22 atthe proximal end of the catheter body 12. In preferred construction ofthe catheter body 12, a force is applied to the proximal end of thestiffening tube 20 which causes the distal end of the stiffening tube 20to firmly push against the counter bore 24. While under compression, afirst glue joint is made between the stiffening tube 20 and the outerwall 22 by a fast drying glue, e.g. Super Glue®. Thereafter a secondglue joint is formed between the proximal ends of the stiffening tube 20and outer wall 22 using a slower drying but stronger glue, e.g.,polyurethane. Any other suitable method of attaching the catheter body12 to the tip section 14 can be used.

Extending through the single lumen 18 of the catheter body 12 are leadwires 40, an injection needle 46, a sensor cable 74, and a compressioncoil 44 through which a puller wire 42 extends. A single lumen 18catheter body is preferred over a multi-lumen body because it has beenfound that the single lumen 18 body permits better tip control whenrotating the catheter 10. The single lumen 18 permits the lead wires 40,the injection needle 46, the sensor cable 74, and the puller wire 42surrounded by the compression coil 44 to float freely within thecatheter body. If such wires and cables were restricted within multiplelumens, they tend to build up energy when the handle 16 is rotated,resulting in the catheter body 12 having a tendency to rotate back if,for example, the handle is released, or if bent around a curve, to flipover, either for which are undesirable performance characteristics.

With reference to FIGS. 3 and 4, mounted at the distal end of the tipsection 14 is a tip electrode 36. Preferably the tip electrode 36 has adiameter about the same as the outer diameter of the tubing 19. The tipelectrode 36 is connected to the tubing 19 by means of a plastic housing21, preferably made of polyetheretherketone (PEEK). The proximal end ofthe tip electrode 36 is notched circumferentially and fits inside thedistal end of the plastic housing 21 and is bonded to the housing 21 bypolyurethane glue or the like. The proximal end of the plastic housing21 is bonded with polyurethane glue or the like to the distal end of thetubing 19 of the tip section 14. Alternatively, the tip electrode 36 canbe mounted directly to the distal end of the flexible tubing 19 of thetip section 14.

Mounted on the distal end of the plastic housing 21 is a ring electrode38. The ring electrode 38 is slid over the plastic housing 21 and fixedin place by glue or the like. If desired, additional ring electrodes maybe used and can be positioned over the plastic housing 21 or over theflexible tubing 19 of the tip section 14.

The tip electrode 36 and ring electrode 38 are each connected to aseparate lead wire 40. The lead wires 40 extend through the third lumen34 of tip section 14, the catheter body 12, and the control handle 16,and terminate at their proximal end in an input jack (not shown) thatmay be plugged into an appropriate monitor (not shown). If desired, theportion of the lead wires 40 extending through the catheter body 12,control handle 16 and proximal end of the tip section 14 may be enclosedor bundled within a protective tube or sheath.

The lead wires 40 are attached to the tip electrode 36 and ringelectrode 38 by any conventional technique. Connection of lead wire 40to the tip electrode 36 is preferably accomplished by weld 43, as shownin FIG. 4.

A puller wire 42 is provided for deflection of the tip section 14. Thepuller wire 42 is anchored at its proximal end to the control handle 16and anchored at its distal end to the tip section 14. The puller wire 42is made of any suitable metal, such as stainless steel or Nitinol, andis preferably coated with Teflon® or the like. The coating impartslubricity to the puller wire 42. The puller wire 42 preferably has adiameter ranging from about 0.006 to about 0.010 inches.

As discussed above, a compression coil 44 is provided in surroundingrelation to a portion of the puller wire 42. The compression coil 44extends from the proximal end of the catheter body 12 to the proximalend of the tip. section 14. The compression coil 44 is made of anysuitable metal, preferably stainless steel. The compression coil 44 istightly wound on itself to provide flexibility, i.e., bending, but toresist compression. The inner diameter of the compression coil 44 ispreferably slightly larger than the diameter of the puller wire 42. Forexample, when the puller wire 42 has a diameter of about 0.007 inches,the compression coil 44 preferably has an inner diameter of about 0.008inches. The Teflon® coating on the puller wire 42 allows it to slidefreely within the compression coil 44. Along its length, the outersurface of the compression coil 44 is covered by a flexible,non-conductive sheath 26 to prevent contact between the compression coil44 and any of the lead wires 40, injection needle 46 or sensor cable 74.A non-conductive sheath 26 made of polyimide tubing is presentlypreferred.

The compression coil 44 is anchored at its proximal end to the proximalend of the stiffening tube 20 in the catheter body 12 by glue to form aglue joint 50 and at its distal end to the tip section 14 in the secondlumen 32, also forming a glue joint 50. The glue may be applied by meansof a syringe or the like through a hole made between the outer surfaceof the catheter body 12 and the single lumen.

The puller wire 42 extends into the second lumen 32 of the tip section14. The distal end of the puller wire 42 is anchored to the tipelectrode 36 or to the side of the catheter tip section 14. Withreference to FIGS. 4 and 5, within the tip section 14, and distal to theglue joint 50, the turns of the compression coil are expandedlongitudinally. Such expanded turns 49 are both bendable andcompressible and preferably extend for a length of about 0.5 inch. Thepuller wire 42 extends through the .expanded turns 49 then into aplastic, preferably Teflon®, sheath 81, which prevents the puller 42from cutting into the wall of the tip section 14 when the section 14 isdeflected.

An injection needle 46 is provided, which extends from the needlecontrol handle through the catheter body 12, through the first lumen 30of the tip section 14 and through a passage 51 in the tip electrode 36.As illustrated in FIG. 3, the injection needle 46 is preferably formedwith a beveled edge at the distal tip of the needle. The needle 46 iscoaxially mounted within a protective tube 47, preferably made ofpolyimide, which serves to prevent the needle from buckling and alsoserves to electrically insulate the needle from the distal electrode 36.The protective tube 47 additionally serves to provide a fluid-tight sealsurrounding the injection needle 46. FIG. 3 depicts the injection needle46 extending beyond the distal end of the tip electrode 36, as it wouldbe positioned in order to infuse diagnostic or therapeutic fluid intothe human heart. The distal end of the injection needle 46 is withdrawninto the tip electrode 36 during the period of time that the catheter isinserted through the vasculature of the body and also during the periodof time in which the catheter is removed from the body to avoid injury.Alternatively, the tip section 14 can be provided without a tipelectrode 36, in which case the distal end of the injection needle 46could be retracted into the first lumen 30 of the tip section 14. Ineither embodiment, the injection needle 46 is extendable and retractablebeyond the distal end of the catheter. If desired, the catheter caninclude a needle stop mechanism for limiting the distance that theneedle extends beyond the distal end of the tip section 14. Such amechanism is described in copending U.S. Patent Application entitled“Injection Catheter with Needle Stop” to Dean Ponzi, filed on even dateherewith, the entire disclosure of which is incorporated herein byreference.

The injection needle 46 is made from one or more straight pieces ofsmall diameter tubing having an outer diameter that allows the tubing tofit within the catheter. Preferably the injection needle 46 has an innerdiameter ranging from about 0.007 inch to about 0.011 inch, and an outerdiameter ranging from about 0.012 inch to about 0.016 inch. Preferablythe injection needle 46 has a total length ranging from about 65 toabout 85 inches, more preferably about 75 inches.

At least one of the pieces of tubing is plastic tubing. In oneembodiment, the entire injection needle 46 consists of a single piece ofplastic tubing. In another embodiment, the injection needle 46 comprisestwo or more discrete pieces of plastic tubing bonded together, end toend, by glue or the like. In another embodiment, the injection needlecomprises a piece of plastic tubing bonded or otherwise attached at oneof its ends to the end of a piece of metal tubing.

The tubing, whether plastic or metal, preferably has straight positionmemory so that when it is bent to a small radius, its natural tendencyis to spring back to the straight position. This property isparticularly important for the tubing that forms the distal region ofthe injection needle (i.e., the portion of the needle within the tipsection 14), because when the tip section is deflected, the needle willdeflect with the tip. When the tip section is then straightened from itsdeflected position, the memory of the tubing forming the distal regionof the needle pushes the tip section back towards the straight positionto the same axis as the catheter body.

Additionally, the tubing, particularly the tubing used for the distalregion of the injection needle, is preferably made of a biocompatiablematerial that is capable of being beveled. The material for the tubingpreferably also has a low coefficient of friction, a good surface finishfor slidability within the catheter, and the ability to be cleaned andsterilized. The good surface finish also reduces coagulate build-up onthe needle. The tubing, particularly the tubing used at the proximal endof the infusion needle, preferably also has the ability to bond or fuseto an adapter for infusion.

A particularly preferred plastic for use in the present invention isPEEK (polyetheretherketone), although other suitable plastics such aspolycarbonate, polyimide, fiberglass, and composites thereof could alsobe used. Suitable metals for use in connection with the presentinvention include Nitinol and stainless steel, although Nitinol ispreferred for use at the distal region of the needle due to itsshape-memory properties. If desired, at least a portion of the tubing,such as the portion that forms the distal region of the needle, isprovided with a lubricious coating, such as Teflon® or silicone,preferably having a thickness ranging from about 0.0003 inch to about0.002 inch. In another alternative embodiment, a biocompatiblelubricant, such as mineral oil is injected around the needle onceassembled.

If desired, the distal end of the injection needle is provide with oneor more fluid openings 45 along its length, as shown in FIG. 3. Thefluid openings 45 can be of any suitable shape, such as round, oval, orrectangular. The fluid openings 45 can be provided only on one side ofthe needle 46, or about the circumference of the needle. The fluidopenings 45 enhance the ability of the drug or other agent passingthrough the needle to weep into the injection side and be more evenlydistributed, allowing for better absorption of the agent by the hearttissue.

Additionally, an electromagnetic sensor 72 is contained within thedistal end of the tip section 14. The electromagnetic sensor 72 isconnected to an electromagnetic sensor cable 74, which extends throughthe third lumen 34 of the tip section 14 through the catheter body 12into the control handle 16. The electromagnetic sensor cable 74comprises multiple wires encased within a plastic sheath. In the controlhandle 16, the wires of the sensor-cable 74 are connected to a circuitboard 64. The circuit board 64 amplifies the signal received from theelectromagnetic sensor and transmits it to a computer in a formunderstandable by the computer. Also, because the catheter is designedfor single use only, the circuit board contains an EPROM chip whichshuts down the circuit board after the catheter has been used. Thisprevents the catheter, or at least the electromagnetic sensor, frombeing used twice. Suitable electromagnetic sensors for use in connectionwith the present invention are described, for example, in U.S. Pat. No.4,391,199 and U.S. patent application Ser. No. 09/160,063, entitled“Miniaturized Position Sensor,” the disclosures of which areincorporated herein by reference. A preferred electromagnetic mappingsensor 72 is manufactured by Biosense Webster, Inc. and marketed underthe trade designation NOGA. To use the electromagnetic sensor 72, thepatient is placed in a magnetic field generated, for example, bysituating under the patient a pad containing coils for generating amagnetic field. A reference electromagnetic sensor is fixed relative tothe patient, e.g., taped to the patient's back, and the injectioncatheter containing a second electromagnetic sensor is advanced into thepatient's heart. Each sensor comprises three small coils which in themagnetic field generate weak electrical signals indicative of theirposition in the magnetic field. Signals generated by both the fixedreference sensor and the second sensor in the heart are amplified andtransmitted to a computer which analyzes the. signals and then displaysthe signals on a monitor. By this method, the precise location of thesensor in the catheter relative to the reference sensor can beascertained and visually displayed. The sensor can also detectdisplacement of the catheter that is caused by contraction of the heartmuscle.

Using this technology, the physician can visually map a heart chamber.This mapping is done by advancing the catheter tip into a heart chamberuntil contact is made with the heart wall. This position is recorded andsaved. The catheter tip is then moved to another position in contactwith the heart wall and again the position is recorded and saved.

The electromagnetic mapping sensor 72 can be used alone or morepreferably in combination with the tip electrode 36 and ring electrode38. By combining the electromagnetic sensor 72 and electrodes 36 and 38,a physician can simultaneously map the contours or shape of the heartchamber, the electrical activity of the heart, and the extent ofdisplacement of the catheter and hence identify the presence andlocation of the ischemic tissue. Specifically, the electromagneticmapping sensor 72 is used to monitor the precise location of the tipelectrode in the heart and the extent of catheter displacement. The tipelectrode 36 and ring electrode 38 are used to monitor the strength ofthe electrical signals at that location. Healthy heart tissue isidentified by strong electrical signals in combination with strongdisplacement. Dead or diseased heart tissue is identified by weakelectrical signals in combination with dysfunctional displacement, i.e.,displacement in a direction opposite that of healthy tissue. Ischemic,or hibernating or stunned, heart tissue is identified by strongelectrical signals in combination with impaired displacement. Hence, thecombination of the electromagnetic mapping sensor 72 and tip and ringelectrodes 36 and 38 is used as a diagnostic catheter to determinewhether and where to infuse a drug into the wall of the heart. Once thepresence and location of ischemic tissue has been identified, the tipsection 14 of the catheter can be deflected so that the injection needle46 is generally normal, i.e., at a right angle, to the ischemic tissue,and the injection needle may then be extended out of the distal end ofthe tip electrode 36 and into the wall of the heart.

It is understood that, while it is preferred to include bothelectrophysiology electrodes and an electromagnetic sensor in thecatheter tip, it is not necessary to include both. For example, aninjection catheter having an electromagnetic sensor but noelectrophysiology electrodes may be used in combination with a separatemapping catheter system. A preferred mapping system includes a cathetercomprising multiple electrodes and an electromagnetic sensor, such asthe NOGA-STAR catheter marketed by Biosense Webster, Inc., and means formonitoring and displaying the signals received from the electrodes andelectromagnetic sensor, such as the Biosense-NOGA system, also marketedby Biosense Webster, Inc.

The electrode lead wires 40 and electromagnetic sensor cable 74 must beallowed some longitudinal movement within the catheter body so that theydo not break when the tip section 14 is deflected. To provide for suchlengthwise movement, there is provided a tunnel through the glue joint50, which fixes the proximal end of the compression coil 44 inside thecatheter body 12. The tunnel is formed by a transfer tube 27, preferablymade of a short segment of polyimide tubing. Preferably the transfertube is approximately 60 mm long and has an outer diameter of about0.021 inch and an inner diameter of about 0.019 inch.

Longitudinal movement of the puller wire 42 relative to the catheterbody 12, which results in deflection of the tip section 12, isaccomplished by suitable manipulation of the control handle 16. As shownin FIG. 8, the distal end of the control handle 16 comprises a piston 54with a thumb control 56 for manipulating the puller wire 42. Theproximal end of the catheter body 12 is connected to the piston 54 bymeans of a shrink sleeve 28.

The injection needle 46 within the protective tube 47, the puller wire42, the lead wires 40 and the electromagnetic sensor cable 74 extendthrough the piston 54. The puller wire 42 is anchored to an anchor pin57 located proximal to the piston 54. The lead wires 40 andelectromagnetic sensor cable 74 extend through a first tunnel 58,located near the side of the control handle 16. The electromagneticsensor cable 74 connects to the circuit board 64 in the proximal end ofthe control handle. Wires 73 connect the circuit board 64 to a computerand imaging monitor (not shown).

The injection needle 46 and protective tube 47 extend through a guidetube 66, preferably made of polyurethane, and are afforded longitudinalmovement therein. The guide tube 66 is anchored to the piston 54,preferably by glue at glue joint 53. This design allows the needle 46and protective tube 47 longitudinal movement within the control handle16 so that the needle 46 does not break when the piston 54 is adjustedto manipulate the puller wire 42. Within the piston 54, theelectromagnetic sensor cable 74 and lead wires 40 are situated within atransfer tube 27 a, and the puller wire 42 is situated within anothertransfer tube 27 b to allow longitudinal movement of the wires and cablenear the glue joint 53.

The injection needle 46, protective tube 47 and guide tube 66 extendthrough a second tunnel 60 situated near the side of the control handle16 opposite the anchor pin 36. To avoid undesirable bending of theinjection needle 46, a space 62 is provided between the proximal end ofthe piston 54 and the distal end of the second tunnel 60. Preferably thespace 62 has a length of at least 0.50 inch and more preferably aboutfrom about 0.60 inch to about 0.90 inch.

In the proximal end of the control handle 16, the injection needle 46,protective tube 47 and polyurethane guide tube 66 extend through asecond larger plastic guide tube 68, preferably made of Teflon®, whichaffords the guide tube 66, injection needle 46, and protective tube 47longitudinal slidable movement. The second guide tube 68 is anchored tothe inside of the control handle 16 by glue or the like and extendsproximally beyond the control handle 16. The second guide tube 68protects the injection needle 46 both from contact with the circuitboard 64 and from any sharp bends as the guide tube 66, needle 46, andprotective tube 47 emerge from the control handle 16.

Extension and retraction of the injection needle 46 out the distal endof the tip electrode 36 is accomplished by the needle control handle 17.As illustrated in FIGS. 2 a and 2 b, the needle control handle 17comprises a generally cylindrical outer body 80 having proximal anddistal ends, a piston chamber 82 extending a part of the waytherethrough, and a needle passage 83 extending a part of the waytherethrough. The piston chamber 82 extends from the proximal end of thehandle part way into the body 80, but does not extend out the distal endof the body. The needle passage 83, which has a diameter less than thatof the piston chamber 82, extends from the proximal end of the pistonchamber to the proximal end of the outer body 80.

A piston 84, having proximal and distal ends, is slidably mounted withinthe piston chamber 82. A Luer connector 86 is mounted in the distal endof the outer body. The piston 84 has an axial passage 85 through whichthe injection needle 46 extends, as described in more detail below. Acompression spring 88 is mounted within the piston chamber 82 betweenthe distal end of the piston 84 and the outer body 80.

The proximal end of the injection needle 46 is mounted to the Luerconnector 86 by means of a first rigid tube 90, preferably made ofstainless steel, which has a proximal end fitted into the Luerconnector. This arrangement fixedly attaches the injection needle 46 tothe piston 84 so that it moves longitudinally with the piston. The firstrigid tube 90 is also fixedly attached to the piston 84 and moveslongitudinally with the piston. The injection needle 46 and first rigidtube 90 extend through the axial passage 85 of the piston 84. Within theaxial passage 85, a second rigid tube 91, preferably made of stainlesssteel, has a proximal end mounted coaxially within the distal end of thefirst rigid tube 90. The proximal end of the second rigid tube 91 ismounted within the protective tube 47, which has its proximal end insidethe axial passage 85, and the distal end of the second rigid tube isattached, directly or indirectly, to the outer body 80. The guide tube66, through which the protective tube 47 and injection needle 46 extend,as discussed above, is fixedly attached to the outer body 80 by means ofa shrink sleeve 92, as is generally known in the art.

In use, force is applied to the piston 84 to cause distal movement ofthe piston relative to the outer body 21, which compresses thecompression spring 88. This movement causes the injection needle 46 tocorrespondingly move distally relative to the outer body, guide tube 66,protective tube 47 and catheter body 12, so that the distal end of theinjection needle extends outside the distal end of the tip electrode 36.When the force is removed from the piston, the compression spring 88pushes the piston 84 proximally to its original position, thus causingthe distal end of the injection needle 46 to retract back into the tipelectrode 36. Upon distal movement of the piston 84, the first rigidtube 91 moves distally over the second rigid tube 91 to prevent theinjection needle 46 from buckling within the axial passage 85.

The piston 84 further comprises a longitudinal slot 100 extending alonga portion of its outer edge. A set screw 102 extends through the outerbody 80 and into the longitudinal slot 100. This design limits thedistance that the piston can be slid proximally out of the pistonchamber 82. When the distal end of the injection needle 46 is in theretracted position, preferably the set screw 102 is at or near thedistal end of the longitudinal slot 100.

The proximal end of the piston 84 has a threaded outer surface 104. Acircular thumb control 106 is mounted on the proximal end of the piston.The thumb control 106 has a threaded inner surface 108 that interactswith the threaded outer surface 104 of the piston. The thumb control 106acts as a stop, limiting the distance that the piston 84 can be pushedinto the piston chamber 82, and thus the distance that the injectionneedle 46 can be extended out the distal end of the catheter. Thethreaded surfaces of the thumb control 106 and piston 84 allow the thumbcontrol to be moved closer or farther from the proximal end of the outerbody 80 so that the extension distance of the injection needle can becontrolled by the physician. A tension screw 110 is provided in thethumb control 106 to control the tension between the thumb control andpiston 84. As would be recognized by one skilled in the art, the thumbcontrol 106 can be replaced by any other mechanism that can act as astop for limiting the distance that the piston 84 extends into thepiston chamber 82, and it is not necessary, although it is preferred,that the stop be adjustable relative to the piston.

In another preferred embodiment constructed in accordance with thepresent invention, two or more puller wires (not shown) are provided toenhance the ability to manipulate the tip section. In such anembodiment, a second puller wire and a surrounding second compressioncoil extend through the catheter body and into separate off-axis lumensin the tip section. The lumens of the tip section receiving the pullerwires may be in adjacent quadrants. The first puller wire is preferablyanchored proximal to the anchor location of the second puller wire. Thesecond puller wire may be anchored to the tip electrode or may beanchored to the wall of the tip section adjacent the distal end of tipsection.

The distance between the distal end of the compression coils and theanchor sites of each puller wire in the tip section determines thecurvature of the tip section 14 in the direction of the puller wires.For example, an arrangement wherein the two puller wires are anchored atdifferent distances from the distal ends of the compression coils allowsa long reach curve in a first plane and a short reach curve in a plane90° from the first, i.e., a first curve in one plane generally along theaxis of the tip section before it is deflected and a second curve distalto the first curve in a plane transverse, and preferably normal to thefirst plane. The high torque characteristic of the catheter tip section12 reduces the tendency for the deflection in one direction to deformthe deflection in the other direction. Suitable deflection controlhandles for use with such a catheter are described in U.S. patentapplication Ser. No. 08/924,611, filed Sep. 5, 1997, entitled“Omni-Directional Steerable Catheter”, Ser. No. 09/130,359, filed Aug.7, 1998, entitled “Bi-Direction Control Handle for Steerable Catheter”,and Ser. No. 09/143,426, filed Aug. 28, 1998, entitled “BidirectionalSteerable Catheter with Bidirectional Control Handle”, and U.S. PatentApplication entitled “Single Gear Drive Bidirectional Control Handle forSteerable Catheter” to Tim Bumbalough, et al., filed Apr. 10, 2000, thedisclosures of which are incorporated herein by reference.

As an alternative to the above described embodiment, the puller wires(not shown) may extend into diametrically opposed off-axis lumens in thetip section. In such an embodiment, each of the puller wires may beanchored at the same location along the length of the tip section, inwhich case the curvatures of the tip section in opposing directions arethe same and the tip section can be made to deflect in either directionwithout rotation of the catheter body.

The preceding description has been presented with reference to presentlypreferred embodiments of the invention. Workers skilled in the art andtechnology to which this invention pertains will appreciate thatalterations and changes in the described structure may be practicedwithout meaningful departing from the principal, spirit and scope ofthis invention.

Accordingly, the foregoing description should not be read as pertainingonly to the precise structures described and illustrated in theaccompanying drawings, but rather should be read consistent with and assupport to the following claims which are to have their fullest and fairscope.

1. An injection catheter comprising: a catheter body comprising aflexible tubing having proximal and distal ends and at least one lumentherethrough; a tip section comprising a flexible tubing having proximaland distal ends, wherein the proximal end of the tip section is mountedat the distal end of the catheter body; one or more electrodes mountedon the tip section; one or more electrode lead wires that correspond innumber to the number of electrodes, each electrode lead wire having adistal end that is electrically connected to a corresponding electrodeon the tip section; a needle control handle at the proximal end of thecatheter body; an injection needle extending through the tip section,catheter body, and needle control handle and having a proximal endattached to the needle control handle and a distal end within the tipsection, wherein the injection needle is longitudinally slidable withinthe tip section so that its distal end can extend beyond the distal endof the tip section upon suitable manipulation of the needle controlhandle, and further wherein the injection needle consists of plastictubing having at least a distal region with straight position memory;and a protective tubing extending through the tip section and catheterbody through which the needle extends coaxially.
 2. An injectioncatheter according to claim 1, wherein the injection needle comprises asingle piece of plastic tubing.
 3. An injection catheter according toclaim 2, wherein the plastic comprises PEEK.
 4. An injection catheteraccording to claim 1, wherein the plastic comprises polycarbonate.
 5. Aninjection catheter according to claim 1, wherein the injection needle isprovided with a lubricious coating on its outer surface.
 6. An injectioncatheter according to claim 5, wherein the lubricious coating comprisesTeflon or silicone.
 7. An injection catheter according to claim 1,wherein the plastic comprises polyimide.
 8. An injection catheteraccording to claim 1, wherein the plastic comprises fiberglass.
 9. Aninjection catheter according to claim 1, wherein the protective tubingis configured to provide a fluid tight seal surrounding the injectionneedle.
 10. An injection catheter according to claim 1, wherein thedistal region of the injection needle is made of a biocompatiblematerial.
 11. An injection catheter according to claim 10, wherein thebiocompatible material is capable of being beveled.
 12. An injectioncatheter according to claim 1, wherein the distal region of theinjection needle has one or more fluid openings.
 13. An injectioncatheter of claim 1, further comprising a needle stop mechanism adaptedto limit a distance the injection needle extends beyond a distal end ofthe tip section.
 14. An injection catheter comprising: a catheter bodycomprising a flexible tubing having proximal and distal ends and atleast one lumen therethrough; a tip section comprising a flexible tubinghaving proximal and distal ends, wherein the proximal end of the tipsection is mounted at the distal end of the catheter body; one or moreelectrodes mounted on the tip section; one or more electrode lead wiresthat correspond in number to the number of electrodes, each electrodelead wire having a distal end that is electrically connected to acorresponding electrode on the tip section; a needle control handleproximal the catheter body; an injection needle extending through thetip section, catheter body, and needle control handle and having aproximal end attached to the needle control handle and a distal endwithin the tip section, wherein the injection needle is longitudinallyslidable within the tip section so that its distal end can extend beyondthe distal end of the tip section upon suitable manipulation of theneedle control handle, and further wherein the injection needlecomprises plastic tubing having at least a distal region with straightposition memory, the injection needle further comprising a piece ofmetal tubing attached at its end to an end of the plastic tubing; and aprotective tubing through which the needle extends coaxially.
 15. Aninjection catheter according to claim 1, further comprising a deflectioncontrol handle proximal of the catheter body and distal of the needlecontrol handle, wherein the injection needle and protective tube extendthrough a guide tube thereby allowing the injection needle andprotective tube longitudinal movement within the deflection controlhandle.
 16. An injection catheter according to claim 15, wherein theguide tube extends at least from the needle control handle and throughthe deflection control handle.
 17. An injection catheter comprising: acatheter body comprising a flexible tubing having proximal and distalends and at least one lumen therethrough; a tip section comprising aflexible tubing having proximal and distal ends, wherein the proximalend of the tip section is mounted at the distal end of the catheterbody; one or more electrodes mounted on the tip section; one or moreelectrode lead wires that correspond in number to the number ofelectrodes, each electrode lead wire having a distal end that iselectrically connected to a corresponding electrode on the tip section;a needle control handle proximal the catheter body; an injection needleextending through the tip section, catheter body, and needle controlhandle and having a proximal end attached to the needle control handleand a distal end within the tip section, wherein the injection needle islongitudinally slidable within the tip section so that its distal endcan extend beyond the distal end of the tip section upon suitablemanipulation of the needle control handle, and further wherein theinjection needle comprises plastic tubing having at least a distalregion with straight position memory; a protective tubing through whichthe needle extends coaxially; and a deflection control handle proximalof the catheter body and distal of the needle control handle, whereinthe injection needle and protective tube extend through a guide tubethereby allowing the injection needle and protective tube longitudinalmovement within the deflection control handle, the deflection controlhandle having a piston for manipulating a puller wire, wherein theinjection needle, protective tube and guide tube extend through a secondtunnel in the deflection control handle and a space is provided betweena proximal end of the piston and a distal end of the second tunnel toavoid undesirable bending of the injection needle.